Innovative Bioplasticizers from Residual Cynara cardunculus L. Biomass-Derived Levulinic Acid and Their Environmental Impact Assessment by LCA Methodology.

This work is focused on the application of Life Cycle Assessment (LCA) methodology for the quantification of the potential environmental impacts associated with the obtainment of levulinic acid from residual Cynara cardunculus L. biomass and its subsequent valorization in innovative bioplasticizers for tuning the properties as well as the processability of biopolymers. This potentially allows the production of fully biobased and biodegradable bioplastic formulations, thus addressing the issues related to the fossil origin and nonbiodegradability of conventional additives, such as phthalates. Steam explosion pretreatment was applied to the epigean residue of C. cardunculus L. followed by a microwave-assisted acid-catalyzed hydrolysis. After purification, the as-obtained levulinic acid was used to synthesize different ketal-diester derivatives through a three-step selective synthesis. The levulinic acid-base additives demonstrated remarkable plasticizing efficiency when added to biobased plastics. The LCA results were used in conjunction with those from the experimental activities to find the optimal compromise between environmental impacts and mechanical and thermal properties, induced by the bioadditives in poly(3-hydroxybutyrate), PHB biopolymer.

Optimization of enzymatic hydrolysis of cellulosic fraction obtained from stranded driftwood feedstocks for lipid production by Solicoccozyma terricola.

Stranded driftwood feedstocks may represent, after pretreatment with steam explosion and enzymatic hydrolysis, a cheap C-source for producing biochemicals and biofuels using oleaginous yeasts. The hydrolysis was optimized using a response surface methodology (RSM). The solid loading (SL) and the dosage of enzyme cocktail (ED) were variated following a central composite design (CCD) aimed at optimizing the conversion of carbohydrates into lipids (YL) by the yeast Solicoccozyma terricola DBVPG 5870. A second-order polynomial equation was computed for describing the effect of ED and SL on YL. The best combination (ED = 3.10%; SL = 22.07%) for releasing the optimal concentration of carbohydrates which gave the highest predicted YL (27.32%) was then validated by a new hydrolysis. The resulting value of YL (25.26%) was close to the theoretical maximum value. Interestingly, fatty acid profile achieved under the optimized conditions was similar to that reported for palm oil.

Yeast lipids from cardoon stalks, stranded driftwood and olive tree pruning residues as possible extra sources of oils for producing biofuels and biochemicals.

BACKGROUND: Some lignocellulosic biomass feedstocks occur in Mediterranean Countries. They are still largely unexploited and cause considerable problems due to the lack of cost-effective harvesting, storage and disposal technologies. Recent studies found that some basidiomycetous yeasts are able to accumulate high amount of intracellular lipids for biorefinery processes (i.e., biofuels and biochemicals). Accordingly, the above biomass feedstocks could be used as carbon sources (after their pre-treatment and hydrolysis) for lipid accumulation by oleaginous yeasts. RESULTS: Cardoon stalks, stranded driftwood and olive tree pruning residues were pre-treated with steam-explosion and enzymatic hydrolysis for releasing free mono- and oligosaccharides. Lipid accumulation tests were performed at two temperatures (20 and 25 °C) using Leucosporidium creatinivorum DBVPG 4794, Naganishia adeliensis DBVPG 5195 and Solicoccozyma terricola DBVPG 5870. S. terricola grown on cardoon stalks at 20 °C exhibited the highest lipid production (13.20 g/l), a lipid yield (28.95%) close to the maximum theoretical value and a lipid composition similar to that found in palm oil. On the contrary, N. adeliensis grown on stranded driftwood and olive tree pruning residues exhibited a lipid composition similar to those of olive and almonds oils. A predictive evaluation of the physical properties of the potential biodiesel obtainable by lipids produced by tested yeast strains has been reported and discussed. CONCLUSIONS: Lipids produced by some basidiomycetous yeasts grown on Mediterranean lignocellulosic biomass feedstocks could be used as supplementary sources of oils for producing biofuels and biochemicals.

Energy from poultry waste: An Aspen Plus-based approach to the thermo-chemical processes.

A particular approach to the task of energy conversion of a residual waste material was properly experienced during the implementation of the national funded Enerpoll project. This project is a case study developed in the estate of a poultry farm that is located in a rural area of central Italy (Umbria Region); such a farm was chosen for the research project since it is almost representative of many similar small-sized breeding realties of the Italian regional context. The purpose of the case study was the disposal of a waste material (i.e. poultry manure) and its energy recovery; this task is in agreement with the main objectives of the new Energy Union policy. Considering this background, an innovative gasification plant (300KW thermal power) was chosen and installed for the experimentation. The novelty of the investigated technology is the possibility to achieve the production of thermal energy burning just the produced syngas and not directly the solid residues. This aspect allows to reduce the quantity of nitrogen released in the atmosphere by the exhaust flue gases and conveying it into the solid residues (ashes). A critical aspect of the research program was the optimization of the pretreatment (reduction of the water content) and the dimensional homogenization of the poultry waste before its energy recovery. This physical pretreatment allowed the reduction of the complexity of the matrix to be energy enhanced. Further to the real scale plant monitoring, a complete Aspen Plus v.8.0 model was also elaborated for the prediction of the quality of the produced synthesis gas as a function of both the gasification temperature and the equivalence ratio (ER). The model is an ideal flowchart using as input material just the homogenized and dried material. On the basis of the real monitored thermal power (equal to about 200kW average value in an hour) the model was used for the estimation of the syngas energy content (i.e. LHV) that resulted in the range of 3-5MJ/m3 for an equivalence ratio (ER) equal to 0.2.

Effect of double-step steam explosion pretreatment in bioethanol production from softwood.

The study investigated the production of bioethanol from softwood, in particular pine wood chip. The steam explosion pretreatment was largely investigated, evaluating also the potential use of a double-step process to increase ethanol production through the use of both solid and liquid fraction after the pretreatment. The pretreatment tests were carried out at different conditions, determining the composition of solid and liquid fraction and steam explosion efficiency. The enzymatic hydrolysis was carried out with Ctec2 enzyme while the fermentation was carried out using Saccharomyces Cerevisiae yeast "red ethanol". It was found that the best experimental result was obtained for a single-step pretreated sample (10.6 g of ethanol/100 g of initial biomass dry basis) for a 4.53 severity. The best double-step overall performance was equal to 8.89 g ethanol/100 g of initial biomass dry basis for a 4.27 severity. The enzymatic hydrolysis strongly depended on the severity of the pretreatment while the fermentation efficiency was mainly influenced by the concentration of the inhibitors. The ethanol enhancing potential of a double-step steam explosion could slightly increase the ethanol production compared to single-step potential.